Rhizome 2-3 mm. diam., far-creeping, much-branched; densely clad in dark brown lanceolate-attenuate squarrose paleae up to 5 mm. long; stipites distant to approximate, articulated to rhizome. Stipes slender, nude or nearly so, very narrowly winged, 1-8 cm. long. Lamina trimorphic, the different forms occurring on the same plant, thin, dull green; main vein stout, prominent, secondary veins and veinlets us. indistinct; anastomoses forming large areoles with included free veinlets: (a) lamina simple, entire, 5-35 cm. × 5-10 mm. linear-lanceolate, tapering to obtuse tip; occasionally bearing sori. (b) lamina 20-30 × 5-10 cm., irregularly pinnatifid, mainly in mid-region; lobes of unequal length sts on one margin only, few to several, sinus wide; lobes 1-5 cm. long, gradually tapering from base up to 10 mm. wide; terminal seg. long; us. bearing sori. (c) lamina repeatedly, less irregularly pinnatifid, up to 35 cm. long; lobes up to 8 cm. long or more, tapering from base 5-10 mm. wide; terminal seg. long; us. with cop. sori. Sori rather distant in a single row on each side of main and secondary veins, near margin; rounded to broad-oblong, 1-2 mm. diam.; slightly sunken, showing as dark spots on upper surface or as bullate protuberances.